Emergency flotation devices are required on many aircraft to provide emergency assistance to passengers and to save the aircraft in the event the aircraft experiences an emergency situation and is forced down in water. Emergency flotation devices generally include systems designed to float the aircraft, systems for emergency life rafts and life vests for individual occupants.
One example of an airplane flotation system is shown in U.S. Pat. No. 1,776,865. The system includes inflatable bags located in a forward portion of an airplane and is manually operated by a pilot. The bags are stored in a non-inflated state within closed compartments. The system utilizes pressure cylinders to sequentially unlock doors of the compartments and inflate the inflatable bags. During operation, the pilot activates the pressure cylinder by pulling a first pull cord attached to a valve, thereby releasing pressurized fluid. After inflation, the pilot is required to second pull a cord that places the pressure cylinder into an intermediate position to block further fluid flow into the bags. The system provides no redundant trigger system.
U.S. Pat. No. 2,264,321 to Manson, describes a life-saving device that includes an inflatable life raft that is arranged in a compartment on the side of a vehicle such as an airplane. The compartment is closed by a pair of hinged doors that are spring-loaded to urge them into an opened position. The doors are held closed by pins that extend through meshing lugs that are included on the doors. A pull cord is secured to the pins and a valve on an inflating-fluid container so that pulling on the cord sequentially removes the pins from the lugs and operates the valve to permit the flow of fluid from the container to the raft. The cord fully disengages from the fluid container after the valve is operated. Similar to the previously described floatation system, this life-saving device provides no redundant trigger system.
In another example of a safety system that may be used for helicopters, described in U.S. Pat. No. 3,340,842 to Winslow, a plurality of balloons fluidly coupled to a pressurized tank of carbon dioxide are employed throughout a vessel. The tank includes an outlet valve fitting that may be operated either by an electrically operated control or a manually operated pull. Both the electrically operated control and the manual pull are coupled directly to the valve fitting on the tank. As a result, replacement of either of the electric control or manual pull would require that the tank be handled, which creates a risk of damaging the tank. In addition, a larger space is required to mount the tank in the vessel because that space must be large enough to accommodate the controls in addition to the tank. Furthermore, because the manual and electric control connect directly to the valve there is no mechanism to assure that one control will not hinder the operation of the other. For example, if the movement of manual control lever was restricted, there is no mechanism that would assure that electric control could be used to release the inflation fluid.
In view of the above, there exists a need for an actuator box assembly for an emergency flotation system that provides the combination of manual and electrical trigger systems all within one assembly that may be mounted separate from the inflation fluid source.